The present paper deals with the kinetic and mechanistic investigation of Os(VIII) catalyzed oxidation of proline by sodium periodate (NaIO4) in alkaline medium in temperature range 300C to 450C. The experimental result shows a first order kinetics with respect to Os[VIII] and [Periodate] while positive effect with respect to substrate i.e., Proline was observed. The reaction showed negative effect for [OH-]. Negligible effect of [HgOAc)2] and ionic strength of the medium was observed. The reaction is carried out in presence of mercuric acetate as a scavenger. The reaction between sodium periodate and proline in alkaline medium shows 2:1 stoichiometry. The values of rate constants observed at different temperatures (30 to 450C) were utilized to calculate the activation parameters. A mechanism involving the complex formation between catalyst, substrate and oxidant has been proposed. L-glutamic acid has been identified as main oxidation product of the reaction chromatographically and spectroscopically. Based on kinetic data, reaction stiochiometry and product analysis of the reaction a feasible mechanism has been proposed. The rate law has been derived from obtained kinetic data.